Shotgun. In the air, is generally how they are fired, since they are used mostly for aerial targets, such as clay pidgeons, real pigeons, crows, dove, quail and pheasants.
Probably just getting tuned up for dove season. In fact there's a wav file with an interview of the old boy who fired the shotgun, and that's what he said he was doing, getting ready for dove season. :)
Listen to the audio! That old boy is PO'd, Big Time. (and not just at the Cindyites, although primarily them.) The local sheriff needs to read the riot act and clear that road, before somebody gets hurt.
On a lighter note, the guy has a good sense of humor too. He called the concentration between the Cindyites and the counter demonstrators "The War of the Porta-Potties". (Wave file)